textproduct: Albany

WHAT HAS CHANGED

Wind gusts have increased for this weekend in the wake of fast moving clipper disturbance with gusty winds in place Saturday through Sunday.

KEY MESSAGES

1) Minor impacts mainly from slippery travel Friday night into early Saturday due to a period of snow showers and potential snow squalls.

2) Moderate to high confidence in very cold temperatures and persistent gusty winds Friday night through Sunday night resulting in dangerous cold and an increased risk for hypothermia and frostbite.

DISCUSSION

KEY MESSAGE 1...

A clipper surface low system will track eastward, closely along the international border to our north, Friday afternoon into Saturday. Aloft, the associated closed cyclone will remain much farther to our north, extending a fairly potent shortwave trough southward into our region about its southern periphery. With the slight deepening of both the closed low aloft and surface cyclone, a fairly steep axis of cyclonic vorticity advection will develop as the shortwave rotates through the region. Despite the enhancement to ascent both in the low- and upper- levels, this will be a rather moisture-starved and progressive system. Therefore, while our next best chance for widespread precipitation can be attributed to this clipper, much of the snow we see will be very light to potentially locally moderate in nature where orographic lifting mechanisms across some of our higher terrain regions can also enhance snowfall.

There are also some hints in the mid- to long-range guidance for a band of mid- to low-level FGEN developing across portions of the region Friday night and/or early Saturday morning. During this same time, the low is anticipated to depart from overhead to the east, allowing a steepening pressure gradient to develop as high pressure builds quickly in its wake over the Great Lakes. And, with forecast soundings indicating a saturated DGZ, there is certainly potential for some stronger snow showers to even snow squalls early Saturday morning along the passage of the potent cold front associated with the clipper low. Still, these would not impact snowfall amounts greatly and being that their occurrence would be early on a weekend day, there luckily wouldn't be much of a societal impact either. In fact, the Weather Prediction Center Probabilistic Winter Storm Severity Index indicates low probabilities (5-20%) for even minor impacts (a few inconveniences to daily life due to winter driving conditions) across the region Friday afternoon into Saturday afternoon from the whole of this system.

KEY MESSAGE 2...

Our days of temperature moderation unfortunately are numbered as another period of dangerously cold conditions is becoming increasingly likely for this weekend. In the wake of the cold front of the aforementioned system, another shot of arctic air will envelope eastern New York and western New England. According to the latest NAEFs, both 700hPa and 850 hPa temperatures will range between 1.5 to nearly 2.5 STDEVs below normal from Friday night through Monday. This will translate to surface temperatures that range from about 2 to 2.5 STDEVs below normal beginning Saturday and lasting through Monday as well.

To make matters feel worse, a lingering cold advection regime behind the front as well as a steepened pressure gradient, especially Saturday, will elevate wind gusts. So, not only will air temperatures be very cold, but wind chill values, or "feels-like" temperatures, will become dangerously cold regionwide. And while winds begin to decrease Sunday and into Monday as high pressure regains control, breezy conditions will continue to make for dangerous wind chills through at least Sunday night and possibly even Monday. At this time, the latest NBM Minimum Temperature QMD probabilities for <1F are about 20 to 90% for Friday night, 40-100% for Saturday night; and 30-100% for Sunday night. Should the NBM maximum wind gust forecast for these time periods verify, wind chill values will be in the 10s to 20s and potentially even 30s below zero. We will continue to monitor trends over the coming days to nail down the exact wind chill forecast. However, know that Cold Weather Advisories and potentially Extreme Cold Watches/Warnings will likely be needed in the near future.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

Through 06z/Wed...VFR conditions will begin the TAF period though there remains potential for widespread low stratus to develop prior to 12z/Tue at all sites. Will continue with IFR/LIFR cigs with some lowering of vsbys also possible but less certain. TEMPO groups were maintained to indicate the possible timing of the stratus development and will make amendments if necessary. Any low stratus will be slow to lift after 12/Tue with an eventual return to MVFR/VFR conditions toward 18z/Tue. Some low stratus may redevelop after 00z/Wed but will hold off on inclusion until the next TAF update. In addition, some light snow showers/flurries could reach some TAF sites near 04-06z/Wed with some reduced vsbys to MVFR or even IFR which will also be introduced at the next update. Wind will be light or out of the west at around 5 kt through the upcoming TAF period.

Outlook...

Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: Moderate Operational Impact. Chance of SHSN. Friday Night: Moderate Operational Impact. Windy With Gusts To 30 kts. Chance of SHSN...SN. Saturday: Moderate Operational Impact. Windy With Gusts To 34 kts. NO SIG WX. Saturday Night: Low Operational Impact. Breezy. NO SIG WX. Sunday: Low Operational Impact. Breezy. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.